Subsea pipeline is used for oil and gas production, for transporting produced fluids from offshore oil and gas reservoirs, as well as for transporting fluids such as gas and water to be injected into offshore reservoirs. Pipeline in offshore oil and gas production is installed on the seabed, often spanning great distances. Hydrocarbon well fluids carried by such pipelines can occur at high temperatures, e.g., greater than about 80° C., even up to about 165° C. Pipeline carrying such high temperature fluids can experience thermal gradients across the pipeline during multiple production shut downs and startups resulting in stresses associated with expansion, contraction, and thermal cycling of the pipeline. This can result in pipeline buckling, movement, and loading that lead to both static peak and cyclic stresses, which may induce overstrain and fatigue failures along the length of the pipeline at locations which are relatively vulnerable and prone to these failure mechanisms. Subsea pipeline transmitting high-temperature fluids, also herein referred to as high temperature pipeline, particularly during shutting down and restarting cycles, is subject to pipeline “walking” in which the pipeline moves away from its intended location. If not mitigated, pipeline walking can lead to failure of subsea pipeline system components such as jumpers, subsea structures and risers. To maintain pipeline system integrity in high temperature pipelines in deepwater oil and gas fields, pipeline end terminations (PLETs) are typically constructed with a sliding mechanism that allows the end of the pipeline to slide back and forth on a fixed foundation so that thermal expansion of the pipeline can be accommodated. This often results in very large, costly PLET structures. As the magnitude of the thermal expansion grows, so does the size and complexity of the PLET design. Very large mud mats are frequently required, e.g., on the order of 60-90 feet long. Very large suction piles installed in the seabed are also frequently used for anchoring the PLET on the seabed. For example, such suction piles can be over 15 feet in diameter and 80-100 feet in length. Larger structures often result in challenges during installation and may require larger installation vessels or increased installation time which result in tremendous additional cost.
It would be desirable to have a solution to the above problems which would control buckling of subsea pipeline, reduce the incidence of pipeline walking, and reduce the need for pipeline anchoring. There is a great economic need for a simpler way to accommodate subsea pipeline stresses and reduce equipment and installation costs.